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Getragdogleg

Original Poster:

4,592 posts

69 months

[news] 
Monday 30th April 2012 quote quote all
I recall reading somewhere an idea that water arrives on Earth from space, presumably vii lumps of ice/meteorites/comet remains.

Is this rubbish or is there a bit of truth that water does indeed come here from space ?

TheHeretic

73,668 posts

141 months

[news] 
Monday 30th April 2012 quote quote all
It doesn't sound ridiculous at all. All matter has been spewed out from stars. Ice comets, and so on will seed the planet with elements, and so on.

http://news.nationalgeographic.com/news/2011/06/11...

jmorgan

20,602 posts

170 months

[news] 
Monday 30th April 2012 quote quote all
Always (whenever I read about it over the last few years) understood it to be there when the planets formed. Also bombardment from the young solar system also carried a lot of stuff in then the general forming of the earth caused it to percolate out etc, volcano building away and all that geological stuff. Of course it needs an atmosphere (pressure?)first I thought.

Eric Mc

77,158 posts

151 months

[news] 
Monday 30th April 2012 quote quote all
ALL the rocks, minerals, gases etc that currently make up the earth (and the other planets) came to be where they are through the accretion process and then the bombardment of the proto-planets by the raw materials that eventually made up those planets. So yes, ALL the water on earth originally came from space.

The state that those materials remained at on earth (i.e. in solid, liquid or gaseous form) depended on the eventual mass of the earth and the conditions pertaining on the planet once the accretion and bombardment phases had eventually quietened down a bit.

The other factor determining how the planet evolved was its distance from the sun.

These factors govern the gravity, atmospheric pressures and temperatures experienced at the surface and, on earth, these are just right to allow water to exist in liquid form over large areas of the planet.

Getragdogleg

Original Poster:

4,592 posts

69 months

[news] 
Tuesday 1st May 2012 quote quote all
I am sat here now wondering how much water (and other stuff) arrives here from space each year, is it measurable ?

I bet if it is it is one of those surprising figures that is larger than you think.
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Use Psychology

11,327 posts

78 months

[news] 
Tuesday 1st May 2012 quote quote all
plenty of matter arrives on earth each year as the gravitational well pulls dust and of course metoerites to the surface.

the biggest loss of mass is from the light gases helium and hydrogen.

overall I think the earth is losing mass, mostly as hydrogen.

interestingly the loss of helium is a future problem since currently the world's helium supply (mostly a store in the US) is being sold at far below it's real value (some US law about how the national helium stocks should be sold off by 20something). Liquid helium is essential for superconducting magnets, so it's used in applications like MRI, spectrometers for chemists and pharmaceutical science, and of course things like CERN. sadly it's also used to fill up cheap helium balloons for children's birthday parties. a huge waste for a limited natural resource of huge importance.

Getragdogleg

Original Poster:

4,592 posts

69 months

[news] 
Tuesday 1st May 2012 quote quote all
With regard to the Helium, Presumably the US have stocks because they condensed it down and stored it in the first place.

It's not a case of the US having all the Helium in the world and when it is gone it is gone, it's more a case of the US having stock that is cheap and when it's gone then everyone else must condense it so it becomes an expensive gas again.

Use Psychology

11,327 posts

78 months

[news] 
Tuesday 1st May 2012 quote quote all
it's actually extracted from natural gas i think but once it's released into the atmosphere it is essentially gone (into space). I don't thin anybody extracts it from air but I could be wrong. All of the helium on earth has been produced since the formation of the planet by radioactive decay (an alpha particle, emitted from nuclei in radioactive decay, is the nucleus of a helium atom).

Edited by Use Psychology on Tuesday 1st May 09:53


Edited by Use Psychology on Tuesday 1st May 10:40

Getragdogleg

Original Poster:

4,592 posts

69 months

[news] 
Tuesday 1st May 2012 quote quote all
Right, I see, but where did the US get it from and why ?


Use Psychology

11,327 posts

78 months

[news] 
Tuesday 1st May 2012 quote quote all
Getragdogleg said:
Right, I see, but where did the US get it from and why ?
extractednatural gas in the US I think, I guess it was stored for military or spacey purposes... or just because they know the world's supply is limited and it is regenerated slowly... then some politicians became aware of the cost of storing it and decided it should be sold off at well below it's true value... duh.

Simpo Two

59,990 posts

151 months

[news] 
Tuesday 1st May 2012 quote quote all
Use Psychology said:
it's actually extracted from natural gas i think but once it's released into the atmosphere it is essentially gone (into space). I don't thin anybody extracts it from air but I could be wrong. All of the helium on earth has been produced since the formation of the planet by radioactive decay (a beta particle, emitted from nuclei in radioactive decay, is the nucleus of a helium atom).
Alpha particle, 4/2 He. A beta particle is an electron.

Helium is also the first product you get from nuclear fusion (ie stars). 1+1=2 etc.

Use Psychology

11,327 posts

78 months

[news] 
Tuesday 1st May 2012 quote quote all
Simpo Two said:
Alpha particle, 4/2 He. A beta particle is an electron.

Helium is also the first product you get from nuclear fusion (ie stars). 1+1=2 etc.
thanks smile edited

Eric Mc

77,158 posts

151 months

[news] 
Tuesday 1st May 2012 quote quote all
Al Quaeda should be targeting the US helium stocks then.

Bedazzled

7,984 posts

107 months

[news] 
Tuesday 1st May 2012 quote quote all
Hydrogen came from the big bang and oxygen from the first stars, and they can join to form water in space... here. But the question is did the water arrive on Earth after it had formed? If water was present very early in the formation of the solar system it could have accreted with other matter as the planets formed, or it could have been delivered to the planet by subsequent impacts.

The theory of our water being delivered to the Earth by comets/meteors is a fashionable one, but does it also explain the vast amounts of water/ice found on moons in the outer solar system such as Enceladus and Europa, and Pluto/Charon, Ceres, etc? Why would water be more likely to accrete in comets, than planets? Or is it more likely that these impacts 'replenish' the water on Earth, but a lot of water was already here?

I don't think there's anything special about the water found on Earth, what's special is the 'lucky' combination of factors that keeps it here, and in liquid form.

Sheets Tabuer

12,290 posts

101 months

[news] 
Tuesday 1st May 2012 quote quote all
Only if they have a dastardly plan to have the whole world talking like alvin and the chipmunks.

Eric Mc

77,158 posts

151 months

[news] 
Tuesday 1st May 2012 quote quote all
Sheets Tabuer said:
Only if they have a dastardly plan to have the whole world talking like alvin and the chipmunks.
I'd call that "The Credibility Bomb". It would transform any world leader into a laughing stock and render him powerless.
The only potential leader it might actually improve is Ed MIlliband.

Simpo Two

59,990 posts

151 months

[news] 
Tuesday 1st May 2012 quote quote all
Eric Mc said:
I'd call that "The Credibility Bomb". It would transform any world leader into a laughing stock and render him powerless.
It would be fun if a small helium nozzle was secreted in Alex Salmond's microphone while he's blithering on about Scottish independence.

PW

2,228 posts

125 months

[news] 
Tuesday 1st May 2012 quote quote all
Eric Mc said:
I'd call that "The Credibility Bomb". It would transform any world leader into a laughing stock and render him powerless.
You wuoldn't be the first http://www.youtube.com/watch?v=w6UhXivPyw4

Eric Mc

77,158 posts

151 months

[news] 
Tuesday 1st May 2012 quote quote all
Damn - I thought I was being original.

XM5ER

3,697 posts

134 months

[news] 
Wednesday 2nd May 2012 quote quote all
http://smallcomets.physics.uiowa.edu/

Arrives all the time allegedly (and unrebuttedly).
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